Prevention and Evaluation Resources Kit (PERK): models and theories

About this page

The information on this page was originally published as an online annex 'Step 2a: Models and theories' to the Prevention and Evaluation Resources Kit (PERK). It is made available here for interested readers but please be aware that the information on this page was last updated on July 2010. For more EMCDDA resources on the topic of drug prevention, please visit our Prevention topic page.

Step 2a: Models and theories

Health promotion

In 1986, WHO (Ottawa Charter) defined health promotion as 'the process of enabling people to increase control over, and to improve, their health. To reach a state of complete physical, mental and social well-being, an individual or group must be able to identify and to realise aspirations, to satisfy needs, and to change or cope with the environment'.

The practice of health promotion is based on a number of theories and models (for example, the health belief model, the theory of reasoned action, the trans-theoretical (stages of change) model, social learning theory, social cognitive theory, the theory of planned behaviour, community development and models of organisational change) with the principal intention of providing information either to improve knowledge or change behaviour.

In practice, health promotion is a generic option aimed at preparing the ground for drug prevention messages and can be seen as its foundation. Its advantage is that it has a non-conflicting principle everybody can agree on.

However, within this broad framework is the question of how detailed concrete and targeted prevention activities are and how far actors are committed to the full consequence of implementation of the WHO principle. There is a difference between including drug prevention under a broader health promotion umbrella, but still specifying its contents and objectives (as most Member States are doing increasingly), and the assumption (without direct evidence) that increased well-being, safe learning, good school climate, etc. alone will have a positive effect on the social risk and protective factors for drug problems. It is important that preventive efforts should be geared not only towards pupils in the school setting, but also to their living environment, thus ensuring structural and normative conditions required for effective drug prevention, but there is no evidence that health promotion alone is sufficient to curb drug problems.


1. Socio-demographic and health variables relating to drugs

Morbidity and mortality
  • Tobacco (rates of disease and number of deaths)
    • Lung cancer 
    • Myocardial infarction
    • Cerebrovascular disease
  • Alcohol (rates of disease and number of deaths)
    • Traffic accidents (deaths)
    • Alcohol-related cardiomyopathy 
    • Alcohol-related psychosis 
    • Alcohol dependency syndrome 
    • Cirrhosis of the liver
    • Chronic pancreatitis
    • Cancer of the oesophagus, others …
  • Other drugs
    • Deaths
    • Number of hospital emergencies relating to non-medical drug use

2. Social problems related to drugs (rates x inhabitants)

  • Unemployment
  • Violence
  • Divorces
  • Numbers of people arrested and prosecuted for drug trafficking
  • Number of prosecutions for drug use in a public place
  • Absenteeism: school and work

3. Variables related to the surroundings/atmosphere

  • Availability of drugs (legal)
    • Sales per capita/annual of litres of pure alcohol to population over 16 years. Food consumption section (Ministry of Agriculture, Fish and Food).
    • Sales per capita/annual of cigarettes to population over 16 years. Commissioner for the Tobacco industry (Ministry of Economy)
    • Publicity and sponsorship of tobacco and alcohol brands
  • Target population. Intermediate variables (not directly referring to drugs)
    • Health behaviour and psycho-social integration

Cognitive models, information-based models

The cognitive models are based on the idea that individuals act according to their knowledge and beliefs; therefore, if individuals are informed about the negative consequences of a certain behaviour, they will make rational and informed choices to modify this behaviour. The main disadvantage of the cognitive models is that they do not account for the gap between intentions and actual behaviour, which in most cases is made up of a broad spectrum of social, emotional and physiological factors which influence behaviour.

Health belief model (HBM)

Knowledge on drugs and attitudes

Leitmotiv: We (intend to) act and decide rationally according to what we know

The health belief model is based on the concept that the perceived risk of disease and the perceived benefits of action to avoid disease are the key factors in motivating a positive health action. So, the provision of factual information about the negative effects and dangers of drugs will deter use or prevent substance abuse by creating negative attitudes towards drug use. The health belief model is a widely recognised conceptual framework for health behaviour. Initially developed in the 1950s in the USA in response to a TB (tuberculosis) screening programme, the model has been used for 50 years to promote a range of health-related action.

This model has, however, important limitations for any behaviour based on more than just simple and fully rational decisions. As an example, let us test the model for the use of condoms to prevent HIV infection among adolescents (the model’s components are in bold):

The perceived level of danger (of HIV infection) can be assumed to be high, the perceived personal vulnerability (to HIV infection) can be assumed to be relatively high (adolescents nowadays are informed), the perceived effectiveness of the preventive measure (using a condom) is high and the perceived chances of effective treatment are low. According to the HBM model, these factors should result in widespread use of condoms by adolescents to prevent HIV. However, in reality, condom use among adolescents is low. This is because several emotional and social factors (e.g. at the moment of initiating sexual intercourse) play a more important role in influencing our behaviours than simply knowledge and perceived risk.

Main variables

  • Knowledge about drugs
  • Knowledge about consequences of drug use

Reasoned action-attitude model

Fishbein and Azjen

Leitmotiv: We (intend to) act and decide upon our own values and considering the norms of others … Behaviour is predicted by intention

The reasoned action theory proposes that an individual’s behavioural intentions have two constituent parts: the individual’s attitude towards the behaviour and the social norms as perceived by the individual. Individuals may weight these differently in assessing their behavioural intentions. Therefore, drug use is a consequence of a rational decision (intention), the belief about this consequence and the social norms towards drug use. In summary, health behaviour is based on your intentions: if you intend to be healthy you will be. The reasoned action model is widely used to explain the motivation behind drug use and offers a convenient structure to examine the relative importance of attitudinal and normative considerations in forming the behaviour of individuals.

Should I? What will the others say?

Main variables

Target population. Variables related to drugs: cognition and behaviour.

  • Intention of drug use in a certain period
  • Perception of risk associated with drug use
  • Perception of acceptance of drug use by peers, parents
  • Perception of drug use in the general population, among young people, among peers.

Social influence models

The social influence models recognise that social factors play a major role in the initiation and early stages of drug use. Social influences may arise from the media, peers and the family. The models are significant because they were the first approaches in prevention designed to essentially change behaviours. The social influence model presents an alternative to other approaches such as information dissemination and affective education, and is the predecessor of ‘competence enhancement’. Social influence models make up several of the core components still used in the most successful prevention approaches

Social learning theory


Leitmotiv: Our behaviour is influenced more by ‘important’ others than by our knowledge or intention

In the 1960s Bandura rejected the behaviourist hypothesis, that one’s environment causes one’s behaviour, as too simplistic. He developed a theory which establishes personality as an interaction between environment, behaviours and an individual’s psychological processes. Also called observational learning, social learning theory emphasises the importance of observing and modelling the behaviours, attitudes and emotional reaction of others. The modelling process is made up of the processes of attention, retention, reproduction and motivation. For example, if someone with a psychological disorder observes someone else dealing with the same problem in a more productive fashion, then the first person will learn by modelling the behaviour of the second person. Another common example of social learning situations are television commercials which suggest, for example, that driving a certain car will make us more popular. We may model the behaviour in the commercial by buying the car. The model is often the basis for peer models and life skills models.

Main variables

Variables related to setting/environment

  • Perception of drug problem in local area
  • Level of parental approval of drug use
  • Parents’ norms in relation to drugs

Target population. Variables related to drugs: cognition and conduc

  • Perception of ease of access to drugs (perceived availability)
  • Buying tobacco/alcohol for parents or family members
  • Experimentation with drugs
  • Perception of the normality of drug use by friends
  • Attitude towards publicity for legal drugs
  • Values

Life skills theory


Leitmotiv: Our interaction with ‘important’ others can be influenced by learning social and personal skills

The life skills theory proposes that, although health-damaging behaviour is the result of a complex interaction between personal, social and environmental factors (Green/Kreuter 1991), behaviour essentially stems from individuals, and individuals should be a focal point for life skills education. The core set of life skills can be divided into problem solving, critical thinking, communication skills, self-awareness and coping with stress (WHO, 1993). The life skills approach is built around creating opportunities for young people to acquire skills that enable them to avoid manipulation by outside influences. It aims to help young people to achieve control over their behaviour while taking informed decisions that can lead to positive behaviour and values. In the USA a popular Life Skills Training programme (LST) address three components found to promote substance use, each component focusing on a different set of skills, i.e. drug resistance skills, personal self-management skills and general social skills.

Although another recent external evaluation suggests that neither LST nor other primary prevention programmes are likely to have a major impact on drug use and drug problems, LST is one of the few programmes that has been extensively evaluated and for which there is research evidence of a small but positive impact on drug use.

Main variables

Target population. Intermediate variables (not directly referring to drugs)

  • Assertiveness
  • Decision-making skills
  • Coping skills
  • Problem-solving skills
  • Social skills

Normative beliefs


Leitmotiv: Our behaviour and our interaction with others is strongly influenced by what we think is ‘normal’ and accepted

Normative beliefs theory bases itself on social ecology theories, which postulate that instead of looking for causes within the individual, or even in the individual's way of interacting socially, we should focus on the social system itself and how that system affects individuals (Hansen). Therefore, efforts to modify substance use must focus on changing the person's environment rather than the person. The term ‘normative belief’ refers to an individual's perceptions about how much his or her close friends use alcohol and drugs and approve of such use. A person who sees the peer group as positively inclined towards substance use is characteristically motivated to use alcohol and drugs as a way of gaining social acceptance. Similarly, those who belong to groups not inclined towards substance use will most likely be inhibited from using alcohol and drugs because of implied and real sanctions from their peer group. The approach deals with the misconception that many adults and most adolescents use drugs. This is sometimes referred to as ‘normative education’. For example, students are provided with information concerning the prevalence rates of drug use among their peers, from either national or local survey data, so that they can compare their own estimates of drug use with actual prevalence rates. 

Main variables

  • Perception of acceptance of drug use by peers, parents
  • Perception and estimation of drug use in the general population, among young people,among peers
  • Perception of media, publicity and social influences on tobacco, alcohol, cannabis use

Sociological and stage models

Sociological and stage models are a new generation of models developed since the mid-1980s which focus on the developmental stages of drug use as an approach to designing effective interventions. The idea is that drug prevention strategies should be developed which target young people at these particular stages of drug use.

Evolution theory models


Leitmotiv: Delaying the first use of legal drugs has an influence on consumption and problems with illegal drugs

This is a group of models based on sequential and evolving theoretical concepts. Substance abuse is developed in a sequential process over several kinds of substances and degrees of deviant behaviour shaped by the social relations in which subjects live, e.g. family history and consumption.

An early example is Kandel’s ‘stage theory’. This theory was presented as a framework around which to develop specific theories of initiation, progression and regression in drug behaviour. Kandel proposed that the earliest stage of drug use involves the use of at least one legal drug (alcohol and/or tobacco), with subsequent stages involving cannabis and other illicit drugs. She also argued that the early onset of drug use is a crucial risk factor for progression to more serious forms of drug use.

Another example which explores the developmental stages of initiation into drug use was developed by Werch and DiClemente and was based on the ‘stages of change’ model developed initially by Prochaska and DiClemente. They adapted the model to describe the development of drug use and a drug habit through a number of stages, starting with pre-contemplation (not considering use), followed by contemplation (seriously considering use), then preparation (intending to use in the near future), action (initiating actual use) and finally maintenance (continuing use). This model is no longer considered useful for prevention.

Social ecology model/ecological-environmental model

Hawkins and Weiss / Kumpfer and Turner

Leitmotiv: To achieve consistent and long-lasting behavioural changes the three social main dimensions of family, school and community need to be involved.

This is a group of models focusing on the macro-social level, social environment, networks in the community/institutions, associations, as well as bonding to family, schools and peers, all of which will influence individuals and their consumption behaviour. The models also include personal variables such as self-efficacy and focus on subjective stress.

The social ecology model was developed by Hawkins and Weiss (1985) and Kumpfer and Turner (1991) and is the most recent theoretical model of prevention interventions. The model proposes that effective prevention approaches should include elements which will improve family and social climate, self-efficacy, school bonding and peer relations. This should be achieved by establishing and maintaining clear rules and boundaries, strong support and rewards for positive behaviour.

Diffusion of innovation theory

New patterns of drug use

Contribution of Deborah Olszewski, Project manager of 'Drug trends in youth' at EMCDDA.

Leitmotiv: To predict the spread of new forms of drug-taking through an understanding who is most likely to try new drugs, how diffusion occurs and why the drug trend occurs.

There is growing evidence that young people may adopt new patterns of drug use in ways that are consistent with the diffusion of innovation theory. The theory does this by focusing on:

  • different types of individuals (innovators and early adopters are those who are most likely to take new drugs; the early majority and late majority comprise those who require increasing network pressure and system norms that strongly favour the use of a new drug before they would use it; and laggards are those who are least likely to take new drugs)
  • the process through which individuals who take a new drug must move (from hearing positive reports about the drug to using it regularly)
  • the attributes of the new drug itself, which affect the likelihood that it will be widely used (its negative effects, how easy it is to try, how easy it is to observe others using, what the relative advantages are and how compatible use is with other valued aspects of social life)

Before young people begin repeated use of a new drug they must go through a process that involves the elements of knowledge, persuasion, decision implementation and confirmation. The process is affected by the attributes of the new drug, such as its negative effects; the ease with which it can be tried and the effects observed; its relative advantages; and, finally, compatibility with the social norms or other, already integrated, drug use.

This theoretical perspective also provides a framework for intervention. It does this by focusing on:

  • different social roles regarding influence ( innovator, opinion leader, change agent and antagonist)

The extent to which innovators can influence their friends and associates may depend on how well they survive their innovative behaviour. Alexander Shulgin might be viewed as one of the more successful innovators. Early adopters, with in-depth knowledge about a new drug and wide social networks, are often used as ‘lieutenants’ in diffusion of harm reduction campaigns. However, categories of drug user are not necessarily static. A person may shift from being an innovator to being an opinion leader as a result of witnessing the death of a friend.

In general, mass media are the main source of information about new drugs. Paradoxically, in this way drug campaigns (or moves to control a new drug) may inadvertently generate awareness that stimulates use of the new drug. A common marketing strategy is to deliberately ‘position’ a new product so that the attributes it shares with other products are emphasised. For example, media coverage can increase the adoption of a drug by ecstasy users by reporting it as a ‘new ecstasy’.

This potential for inadvertently stimulating drug use means that interventions and legislative controls should take into account the role of the media and devise strategies for working with the media to influence the methods of reporting and the positioning of drugs in relation to others that are used widely.


  • Golub, A. and Johnson, B. (1996), ‘The crack epidemic: empirical findings support an hypothesized diffusion of innovation process’. Psychopharmacology 53, pp. 97–102.
  • Rogers, E. (1995) Diffusion of Innovations, 4th edition. New York: Free Press.
  • Ferrence, R. (2001), ‘Diffusion theory and drug use’. Addiction 96, pp. 165–73.

Comprehensive and social influence models

Based on the social influence model, the comprehensive social models present the concept of risk and protective factors which influence young people’s attitudes and behaviours with regard to substance use. Connectedness/bonding and resilience emerge as themes. Connectedness refers to a sense of belonging, and having strong and meaningful connections to family, school, peers and the community. Resilience refers to the quality that helps people deal with problems and demands that may confront them, and to respond well to a range of life events. In both these areas, parental support and adult role models are important. Comprehensive social influence models provide the basis of many successful prevention programmes and in particular for selective prevention. They offer practical and positive actions and responses even in difficult situations.

Problem behaviour model

Jessor and Jessor

Leitmotiv: Drug use is just one possible manifestation of a predisposition to problematic behaviours

This theory focuses on the dynamic interrelation of behaviour (conventional or not), environment (social control and support) and personality, thus explaining problematic behaviour. Early-onset antisocial behaviour predicts later drug use. There is an emphasis on socialisation processes and on the perception of the adequacy of behaviours, for instance on the link between delinquency, drug use and unprotected sex.

The problem behaviour model acknowledges that young people’s behaviour is the result of complex interactions between them and their environment, taking into account the interrelationships between cognitive, attitudinal, social, personality and behavioural factors. Young people engage in problem behaviour such as illicit drug use in order to help them achieve personal goals. Such behaviour is seen as functional – for example, coping with failure, boredom, unhappiness, social isolation or low self-esteem. The theory suggests that the likelihood of engaging in illicit drug use is greater for those young people who have fewer effective coping strategies, fewer social skills and greater social anxiety. Jessor and colleagues established risk and protective factors related to personality systems, perceived environment and behaviour that influence young people’s problem behaviour. They were able to confirm a significant inverse relationship between protective and risk factors, illustrating that the greater the protection, the less the problem behaviour.

Main variables

Variables related to setting/environment

  • Drug use by people within sphere of influence (friends, relatives …)

Target population. Intermediate variables (not referring directly to drugs)

  • Susceptibility to persuasion
  • Social and antisocial behaviour

Social development model

Hawkins and Catalano

Leitmotiv: Resiliency is like the response of a rubber duck to being squeezed: ‘it makes a sound of stress, but it immediately recovers its original shape’.

The social development strategy proposes that successful bonding to the family, school, community and peers will provide young people with the best prospect of becoming strong and healthy adults. In contrast, poor bonding in these areas is more likely to lead to deviant behaviour and substance use. Hawkins and Catalano suggest that within each area, and in order to bond, young people need to have meaningful opportunities to feel lovable, capable and important, the skills required to take advantage of those opportunities, and the messages need to be continually reinforced if the effects are to be continued to be applied. The social development model provides the theoretical basis for risk reduction and protective focused prevention and seeks to promote achievement and success as well as prevent and treat health and behaviour problems among young people. It challenges research that focuses on problem behaviours and risk factors, and instead proposes a model that focuses on protective factors that can help young people develop the ‘resilience’ needed to resist alcohol and other drug use.

Main variables

Variables related to the settings/environment

  • Family socialisation, educative strategies of parents    
  • Health behaviour and psychosocial integration
  • Adaptation to immediate environment (inadequate socialisation)
  • Motivation and class attendance
  • Familiar cohesion
  • Perception of family/parental conflict

Target population. Intermediate variables (not referring directly to drugs)

  • Perception of family/parental conflict